The following patents in the name of one or both of the present inventors relate to web feeding, cutting and dispensing machines whose installations are more complex than the described machines embodying the present invention, because the prior machines disclosed in these four patents all require pneumatic power in addition to electric power:
______________________________________ U.S. Pat. No. Issue Date Inventors ______________________________________ 4,151,770 May 1, 1979 Joseph J. D'Angelo Lawrence S. Maccherone 4,207,667 June 17, 1980 Joseph J. D'Angelo Lawrence S. Maccherone 4,699,031 Oct. 13, 1987 Joseph J. D'Angelo Joseph J. D'Angelo, Jr. 5,020,403 June 4, 1991 Joseph J. D'Angelo Joseph J. D'Angelo, Jr. ______________________________________
The present invention provides machines performing web feeding, cutting and dispensing of cut sheets of packaging material. These machines are compact and their installations are less complex overall than prior machine installations, because the present machines are all-electric, self-contained operating units without requiring pneumatic power in addition to electric power. The need for compressed air is eliminated, thereby eliminating the floor space and the expense involved in compressor installations which usually include pressure tanks, compressed-air coolers, air lines, filters, valves and pneumatic connections. Furthermore, elimination of compressor installations avoids the noise associated with active compressors and their frequently operating drive motors.
Machines embodying the present invention utilize a travelling knife cut-off operation in distinction to a hot-wire cut-off operation. It has been found that use of a hot wire for cutting foam plastic sheets liberates fumes, vapor and/or smoke as the hot wire melts through plastic material along the length of a cut line. These fumes, vapor and/or smoke condense into deposits on nearby room-temperature components of hot-wire machines. Such deposits relatively rapidly build-up to significant thicknesses, thereby requiring "down time" for clean-up of the machines. Moreover, in certain cases, exhaust ducts and associated suction blowers and filters may be required to remove fumes, vapor and/or smoke from plant facilities wherein groups of hot-wire machines are in use.